Island



Nov. 10,1925- 1561311 J. w. CRAIG- DRAF'I' REGULATING DEVICE Filed Dec.21, 1922 hwtvvvoa JAMtS w. CRMQ Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

JAMES W. CRAIG, OF PROVIDENCE, RHODE ISLAND.

DRAFT-REGULATING DEVICE.

Application filed December 21, 1922.

To all whom it may concern:

Be it known that I, JAMES W. CRAIG, a citizen of the United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements in Draft-Regulating Devices, of which the following is a specification.

This invention relates to an improved draft regulating device forfurnaces.

One object of the invention is to provide a device of this characterwherein the control of the gases from the combustion chamber may be moreefficiently controlled than in the case of devices of this characterheretofore used. 1

Other objects and advantages of the invention relate to various improveddetails of construction and methods of operation as will be more fullyset forth in the detailed description to follow.

Referring to the accompanying drawings:

Fig. 1 is a side elevational view of the exit pipe showing the means foradjusting the position of the draft regulator.

Fig. 2 is a vertical sectional view taken along the line 6-6 of Fig. 1,and showing the position of the draft regulator and its associated partswhen in normal operative position.

Fig. 3 is a view similar to Fig. 2, showing the relation of the partswhen the rod is in position to be withdrawn from the damper plate, and,

Fig. 4 is a detail sectional view, taken along the line 8-8 of Fig. 2.

A pipe 41- from the furnace provides a passage through which the exitgases pass from the furnace, the pipe being provided with a novel formof damper for controlling the flow of exit gases through the pipe.

The damper 42 is positioned in the pipe 41 and rotatably supported by arod 43 for movement to vary the quantity of exit gases passing throughthe pipe. Fixed to the outer end of the rod 43 by means of lock nuts 44or other suitable means is a pointer 44,

while a segmental scale 45, having suitable indicia thereoncorresponding with the indicia carried by the shoulder 31, is fixed -tothe pipe 41.

The damper42 comprises an outer plate member 47 fitting closely withinthe pipe 41 and having an opening 48 therein within which fits an innerplate member 49. The inner plate member 49 is firmly secured withinSerial No. 608,225.

the opening 48 and to the outer plate member 47, to form therewith whatis in effect unitary plate member all parts of which lie insubstantially the same plane, by means of suitable fastening devices 50.One or more ports 51 are provided, preferably in the inner plate member,and shutters 52 are pivotally mounted, in this instance upon the outerplate member, for movement over the ports 51 to wholly or partiallycover the same, the shutters being each adapted to be secured in any oneof a plurality of adjusted positions by means of thumb nuts 53, wherebyany desired degree of closure for the ports 51 may be secured. The rod43, to which the pointer 44 is secured, is surrounded by a coiled spring55 positioned between a portion of the segmental scale member 45 and oneof the nuts for securing the pointer to the rod, which spring constantlyacts to urge the rod outwardly from the pipe. The rod 43 is providedwith oppositely directed bends 57 and 58 formed therein adjacent to eachother and suitably located adjacent to a depression 59 formed in theinner plate 49 when the rod is in operative position. The outer andinner plate members are formed with struck out portions 60 and 61respectively to form a channel for the reception of the rod 43, thesestruck out portions being in line with the depression 59 abovementioned. The depression 59 extends somewhat farther from the plane ofthe damper than the struck out portions to permit the rotation thereinof that portion of the rod containing the bends 57 and 58, and shoulders62 and 63 and are formed in the depression suitably positioned forengaging the opposite bends 57 and 58 respectively when the rod 43 isrotated into the position shown in Fig. 6 and pressed outwardly by thespring 55. In this position of the parts the rod is held by theshoulders 62 and 63 against rotation relative to the damper so that anyrotative movement of the rod results in a corresponding movement of thedamper to open or close the pipe to the pas sage of exit gasestherethrough. When it is desired to remove the damper the rod can bereadily removed by pressing inwardly upon the pointer 44 against thespring 55 until the bends 57 and 58 clear the shoulders 62 and 63respectively whereupon the rod can be rotated independently of thedamper, and when turned through forty-five degrees, will occupy theposition shown in Fig. 7,

whereupon it can be withdrawn from the pipe. ft will, of course, beunderstood that in assembling the parts the rod will be first insertedin the position shown in Fig. 7 and rotated into the position shown inFig. 6, whereupon when pressure upon the rod is released the spring 55will force it outwardly and bring the bends 57 and 55: into engagementwith the shoulders 62 and 63 to hold the rod against rotation relativeto the damper.

In the use of my improved damper construction I propose to form theinner plate 4-9 of a single standard size and contour for allinstallations and form a plurality of outer plates of different over-allsizes to lit pipes of varying diameters. Each of the outer plates isformed with an opening 48 properly located and of suitable size andshape to receive the inner plate which Will be of the same size andshape in all cases. It will be noted that the inner plate member iseccentrically positioned relative to the outer plate member, that is, inall sizes of the outer plate member the inner edge of the opening 18 onthe rod 43 nearest to the wall of the pipe 41 as indicated by B isalways spaced an equal distance from the Wall of the pipe ,ll, wherebythe bends in the rod 43 will always occupy the same position withrelation to the shoulders 62 and (53 formed in the inner plate member'-regardless of the over-all size of the outer plate member. Thus in allcases except the smallest possible over-all size of the outer platemember, the inner plate member willbe eccentrically located relative tothe outer plate member. This construction permits the use of the samerod and inner plate member in any possible installation, the outer platemember being varied in over-all size as desired to fit closely withinpipes 41 of varying size. Attention is also called to the fact that inaddition to the provision for a graduated basic flow of gases asprovided by means of the ports 51 and shutters 52 therefor, the pointermay be rotated relative to the rod d3 by loosening one of the lock nutsemployed for securing the same thereon, whereby the pointer may besecured to the rod 43 so that when the pointer is directed the zero markon the scale damper will either occupy a vertical position in the pipeto entirely close the same, or may be held at any desired small anglefrom the vertical to secure a suitable basic flow depending upon theparticular conditions of basic draft required, that is, in adjusting thebasic draft the portsfil maybe set fully open if desired and if thebasic draft thus obtained is insufticient the position of the pointerrelative to the rod 43 may be varied so that the damper will occupy aposition at greater or less angle to the vertical when the pointer isdirected to the zero point of the scale. In

this way I am enabled to apply the damper to pipes having a variety ofdifferent diameters without the trouble and expense of keeping in stocka variety of complete dampers. By means of this construction I amenabled to furnish dampers in one-fourth inch sizes instead of one inchsizes as has been the case heretofore without the excessive 00st. ofcarrying the great number of complete dampers which would be necessaryto fit thus closely the various pipes now in use. iiIOI'BQVQl', by thismeans I am enabled to secure more perfect fitting between the damper andthe interior wall of the pipe and thus reduce, where desired, the flowof exit gases and secure a wider range of control over the flow of thegases from the combustion chamber. The provision of the ports 51, andshutters 52 therefor permits an extremely delicate regulation of thebasic flow of gases, that is, when the damper is closed, and by rotatingthe damper the flow of gases may be increased as may be desired over thebasic flow determined upon after a survey of the size of the furnace,conditions of draft, etc.

The draft regulating means may be set to control the flow of exit gasesin accordance with a means for regulating the supply of gases to thecombustion chamber. The tie gree of permanent closure of the passage inthe pipe 41 may be varied by properly positioning the shutters 52.

lVhile I have shown and described with considerable particularity oneform which my invention may assume in practice, I am aware that variouschanges in the form and arrangement of the parts may be made by oneskilled in the art, and I do not desire, therefore, that the descriptivematter herein contained be understood as limiting my invention to theprecise form shown and described but it is my intention that thedescription of the method of positioning and arranging the various partsbe regarded as illustrative rather than in a limiting sense.

hat I claim is.:

1. In a draft regulating device for furnaces, a damper comprisin aninner plate member, a rod rotatable in and supporting said inner platemembers, cooperating means carried by said rod and inner plate memberengageable in one longitudinal position of said'rod for holding said rodand inner plate member against relative rotation, an outer plate memberhaving its external circumference of suitable size to fit within thepipe and provided with. an opening for receiving said inner platemember, and means for securing said inner plate member within theopening formed in said outer plate member whereby said inner platemember may be secured to outer plate members of diflerent sizes while sopositioning the cooperating means carried by said rod and inner platemember as to hold the rod and inner plate member against relativerotation.

2. In a draft regulating device for furnaces, a damper comprising anouter plate member provided with an opening eccentrically positionedrelative to the perimeter of said outer plate member, an inner platemember fitting Within the opening formed in said outer plate member andfirmly secured to said outer plate member, and a rod engaging said innerplate member i'or rotating said inner and outer plate members as a unitwhereby the inner plate member may be used With outer plate members ofdifferent sizes.

In testimony whereof I have aflixed my signature.

JAMES W. CRAIG.

